I suppose, just for the sake of discussion, one might argue that comparison of 'tall' WR vs 'short' is really more about comparing a 6'4" guy to a 5'9" one. The big one has advantages in certain plays vs a small corner @ 5'10 or so. In my view, the height advantage is most beneficial in those fade patterns into the corner of the end zoen on plays snapped inside the 10. The QB can throw it high and over the reach of the corner. With a great throw, almost impossible to defend really. On plays in the middle of the field, receiver height is helpful on the throws a little high, etc. But the smaller receivers seem, in my view, to have advantage in running after the catch and getting the low throws, etc. I think you like to some of each for packages and particular circumstances and creating mismatches. The 6'1 guy is kind in between. I put the 6' and under guys in the small category and 6'2 and up in the big category. I suppose the ideal tall receiver is now around 6'5". The little ones (now under 5'10") are going to become few and far between. A guy like Johnny Rodgers at about 5'8" (maybe?) would likely get overlooked by many programs today. Riley obviously is looking for pure speed, hands, elusiveness and blocking skills presumably. I do think players weighing less than 170 lbs are going to be limited and at risk for some tough hits as safeties and LBs and even corners are now at or over 210 often tiimes. Giving up 4" and 40 lbs or more is tough.